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author | OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> | 2008-10-15 22:50:28 (GMT) |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2008-10-23 09:13:16 (GMT) |
commit | e2761a1167633ed943fea29002f990194923d060 (patch) | |
tree | e91816e85c7721fcff72e5f84336b1dde9d1ac17 /fs | |
parent | 871c0067d53ba2dc35897c7da1da675bf4c70511 (diff) | |
download | linux-e2761a1167633ed943fea29002f990194923d060.tar.xz |
[PATCH vfs-2.6 2/6] vfs: add d_ancestor()
This adds d_ancestor() instead of d_isparent(), then use it.
If new_dentry == old_dentry, is_subdir() returns 1, looks strange.
"new_dentry == old_dentry" is not subdir obviously. But I'm not
checking callers for now, so this keeps current behavior.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/dcache.c | 45 | ||||
-rw-r--r-- | fs/namei.c | 22 |
2 files changed, 33 insertions, 34 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index c6fd1f2..6402400 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1720,18 +1720,23 @@ void d_move(struct dentry * dentry, struct dentry * target) spin_unlock(&dcache_lock); } -/* - * Helper that returns 1 if p1 is a parent of p2, else 0 +/** + * d_ancestor - search for an ancestor + * @p1: ancestor dentry + * @p2: child dentry + * + * Returns the ancestor dentry of p2 which is a child of p1, if p1 is + * an ancestor of p2, else NULL. */ -static int d_isparent(struct dentry *p1, struct dentry *p2) +struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2) { struct dentry *p; for (p = p2; !IS_ROOT(p); p = p->d_parent) { if (p->d_parent == p1) - return 1; + return p; } - return 0; + return NULL; } /* @@ -1755,7 +1760,7 @@ static struct dentry *__d_unalias(struct dentry *dentry, struct dentry *alias) /* Check for loops */ ret = ERR_PTR(-ELOOP); - if (d_isparent(alias, dentry)) + if (d_ancestor(alias, dentry)) goto out_err; /* See lock_rename() */ @@ -2155,31 +2160,27 @@ out: * Caller must ensure that "new_dentry" is pinned before calling is_subdir() */ -int is_subdir(struct dentry * new_dentry, struct dentry * old_dentry) +int is_subdir(struct dentry *new_dentry, struct dentry *old_dentry) { int result; - struct dentry * saved = new_dentry; unsigned long seq; - /* need rcu_readlock to protect against the d_parent trashing due to - * d_move + /* FIXME: This is old behavior, needed? Please check callers. */ + if (new_dentry == old_dentry) + return 1; + + /* + * Need rcu_readlock to protect against the d_parent trashing + * due to d_move */ rcu_read_lock(); - do { + do { /* for restarting inner loop in case of seq retry */ - new_dentry = saved; - result = 0; seq = read_seqbegin(&rename_lock); - for (;;) { - if (new_dentry != old_dentry) { - if (IS_ROOT(new_dentry)) - break; - new_dentry = new_dentry->d_parent; - continue; - } + if (d_ancestor(old_dentry, new_dentry)) result = 1; - break; - } + else + result = 0; } while (read_seqretry(&rename_lock, seq)); rcu_read_unlock(); @@ -1454,20 +1454,18 @@ struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex); - for (p = p1; !IS_ROOT(p); p = p->d_parent) { - if (p->d_parent == p2) { - mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT); - mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD); - return p; - } + p = d_ancestor(p2, p1); + if (p) { + mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT); + mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD); + return p; } - for (p = p2; !IS_ROOT(p); p = p->d_parent) { - if (p->d_parent == p1) { - mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); - mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); - return p; - } + p = d_ancestor(p1, p2); + if (p) { + mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); + mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); + return p; } mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |